U.S. patent number 3,819,190 [Application Number 05/294,363] was granted by the patent office on 1974-06-25 for golf ball.
Invention is credited to Fred E. Holmstrom, Daniel A. Nepela.
United States Patent |
3,819,190 |
Nepela , et al. |
June 25, 1974 |
GOLF BALL
Abstract
A golf ball having controllable flight characteristics and
comprised of a standard sized spherical body with surface
depressions located in a band extending therearound and the surface
portions outside this band having fewer, or no, depressions to
decrease the drag on the ball while leaving the lift
characteristics substantially the same thereby to cause the ball,
for a given striking force, to exhibit directional control.
Inventors: |
Nepela; Daniel A. (Saratoga,
CA), Holmstrom; Fred E. (San Jose, CA) |
Family
ID: |
23133087 |
Appl.
No.: |
05/294,363 |
Filed: |
October 2, 1972 |
Current U.S.
Class: |
473/383 |
Current CPC
Class: |
A63B
37/0074 (20130101); A63B 37/0096 (20130101); A63B
37/0011 (20130101); A63B 37/0004 (20130101); A63B
37/009 (20130101); A63B 37/0006 (20130101) |
Current International
Class: |
A63B
37/00 (20060101); A63b 037/14 () |
Field of
Search: |
;273/232,213,199,235,233,234 ;40/327 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Marlo; George J.
Attorney, Agent or Firm: Moore; Gerald L.
Claims
We claim:
1. A golf ball including a cover having a plurality of depressions
at spaced locations on the surface thereof adapted to exert a
lifting force on the ball as it spins during flight, and said
depressions being located to cause greater surface air turbulence
adjacent a single circumferential band extending around the ball
thereby to affect the air flow therearound and render control over
the direction of flight of the ball as the ball spins about an axis
generally perpendicular to the plane of the band during flight.
2. A golf ball as defined in claim 1 wherein said surface
depressions are dimples in the ball surface.
3. A golf ball as defined in claim 1 wherein said surface
depressions are positioned in a circumferential band extending
around the ball surface and centered about the circumferential
line.
4. A golf ball as defined in claim 3 wherein depressions are
located on the ball surface at places other than within the band
but spaced farther apart than those within said band.
5. A golf ball as defined in claim 3 wherein the depressions are
located both within and outside the band but those within the band
are shaped to cause a greater air turbulence than those outside the
band.
Description
BACKGROUND OF THE INVENTION
This invention relates to an improvement in a golf ball having as
its primary purpose the making of a golf ball that will travel
substantially the same distance as a conventional ball while giving
the player more control over the direction the ball travels.
Golf balls used today comprise a spherical body made of a solid
resilient material. The outer layer of the ball is "dimpled" to
form depressions to increase the lift forces imparted on the ball
when it is hit. When properly struck, the ball will rise in flight
and spin about a horizontal axis such that the bottom of the ball
moves in the direction of flight and the top moves opposite to the
direction of travel. Imparting lift to the ball requires that a
film of air immediately adjacent the ball surface spins with the
ball. This air film at the top of the ball is moving in the same
direction as the air passing over the ball and thereby serves to
increase the velocity of the air at that point. Thus the air
pressure at the top surface of the ball is lower than elsewhere on
the ball. At the same time the air film at the bottom of the ball
is reacting against the ambient air flow in a manner to slow the
passing air and increase the pressure at that point. The result is
a greater atmospheric pressure at the bottom of the spinning ball
than at the top, thereby supplying a lifting force tending to carry
the ball farther.
As a golf club impacts with a conventional golf ball on the ground,
or on a tee, two effects occur. (1) The ball acquires translational
velocity in the intended direction, and (2) the ball spins about an
axis of rotation. The direction the axis of spin takes, or is given
with respect to the ground and the amount of spin imparted to the
ball are the primary factors in determining what, if any,
additional range may be acquired by the ball or whether it will
hook or slice upon leaving the club.
In general, the lifting force increases if the ball spins faster
during flight. However, the spin speed imparted to the ball is
substantially constant for each golf club and a given tee height.
An important factor affecting the lift is the thickness of the
boundary film of air spinning with the ball. To increase this
thickness, dimples or depressions are formed in the ball surface
which cause localized areas of turbulence. Turbulence tends to
increase the thickness of the air film spinning with the ball
thereby increasing the lifting forces imparted on the ball.
However, a negative effect is realized also when a dimpled surface
is utilized. The force tending to slow a conventional ball as it
travels through the air is commonly referred to as drag. The drag
is proportional to the planar area of the ball pushing through the
air. With the air film spinning with the ball, the effective planar
area of the ball is increased thereby increasing the drag forces
imparted on the ball. Naturally any detrimental forces acting to
slow the ball in flight will reduce the distance the ball
travels.
One other detrimental effect of increasing the lift of the ball
occurs when the ball is hit imperfectly, which act results all too
often with the average golfer. In hitting the ball, if the club
face is not traveling in the same direction it is desired for the
ball to take, i.e., with the planar surface normal to that
direction, a sidewise spin is imparted to the ball causing forces
to act thereon similar to those imparting lift. In this manner the
ball is forced to one side or the other of the intended flight path
resulting in a curved flight commonly called a "hook" or "slice"
depending on the direction of the spin. Some golfers more expert at
the game use an intentional hook or slice to improve their game,
but most golfers attempt to hit the ball straight for best
results.
It is the primary objective of this invention to provide a golf
ball with substantially the same range as a conventional ball but
incorporating a depression design on the surface of the ball that
can be oriented on the tee, or with respect to the axis of spin, so
that as the ball spins in flight, the lift, hook or slice
properties of the ball are influenced.
SUMMARY OF THE INVENTION
A golf ball including a cover having the depressions therein
centered adjacent a single plane passing through the geometric
center of the ball in a manner to affect the air flow past the ball
during flight and render control over the direction of flight of
the spinning ball.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a prior art golf ball having the surface depressions
distributed evenly over the total surface;
FIG. 2 is a view along the lines 2--2 of FIG. 1;
FIG. 3 shows one preferred embodiment of the invention wherein
dimple type depressions are positioned in a band about a
circumferential line extending around the ball;
FIG. 4 shows another preferred embodiment of the invention wherein
the surface depressions comprise grooves extending through a band
portion about the ball; and
FIG. 5 shows still another embodiment wherein the total ball
surface is dimpled, however, the density of the dimples is
increased within a center band extending around the ball.
DESCRIPTION OF PREFERRED EMBODIMENTS
In FIG. 1 is shown an example of a commonly used golf ball
comprising a spherical body 10 of resilient material with the
surface thereof having formed therein a plurality of evenly
distributed and spaced depressions or dimples 11 provided to
increase the lift on the spinning ball in flight in the manner
previously described. Thus if the ball is travelling in the
direction of the arrow 12 the natural "back" spin imparted to the
ball at the impact of the club (not shown) and the ball will be in
the direction of the arrow 13 about a spin axis 14 extending out of
the plane of the drawing.
Referring now to FIG. 2, the ball of FIG. 1 is shown spinning in a
direction with the surface being seen travelling downward relative
to the drawing and with the ball travelling in a direction into the
paper. The spin axis is shown as the dotted line 14 extending
through the geometric center of the ball.
To illustrate the net atmospheric force tending to lift the ball,
two arrows are drawn extending in a direction normal to the ball
surface. Arrow 15 illustrates a lifting force acting on the bottom
of the ball and resulting from the interaction of the film of air
spinning with the ball as heretofore described. Arrow 16
illustrates a downward pressure imparted in the ball having a
smaller force (as shown by the length of the arrow) than the
lifting force thereby resulting in a resultant force acting to move
the ball upward in the manner previously described.
At the same instant, all the surface is being acted on by
atmospheric pressure with the differences being that the total
forces have less effect on the flight of the ball than do those
acting on a central band about the center of the ball.
For instance, arrow 17 representing a force acting at a point close
to the intersection of the ball surface and the spin axis is
comprised of force arrows 18 and 19. The vertical arrow 18
indicates a slight lifting force on the ball but unfortunately most
of the force consists of that indicated by the arrow 19 acting to
push the ball to the side because of the location of the point at
which the force acts. Of course, the sidewise direction force 19 is
offset by another force acting in the opposite direction on the
other side of the ball. Additionally the total force acting at this
point is less than those nearer arrow 15 since the ball surface
velocity, and therefore the velocity of the air film travelling
with the surface, is less than that at arrow 15.
However, the air film over the total surface is nearly uniform in
thickness due to the even distribution of the dimples in the ball
surface. The thickness of the air film adds to the overall drag
area of the ball thereby contributing to the drag forces imparted
on the ball thus tending to slow it down while in flight. The air
film in the "polar" regions about the spin axis contribute to the
drag while contributing little or nothing to the overall lift
imparted on the ball.
In accordance with the present invention, the dimples or surface
depressions on the ball surface are concentrated in a
circumferential band centered about a circumferential line around
the ball. If the ball is teed with the plane of the band aimed
along the desired direction of flight, the lift characteristics of
the ball remain substantially unchanged over a conventional ball
since, as shown heretofore, those areas external to the
circumferential band contribute little to the lift imparted on the
ball when spinning about the axis 26.
By making the surface regions outside theband smoother, i.e., fewer
dimples, less air turbulence results and a thinner film of air is
carried by these areas thereby reducing the drag on the ball while
not appreciably affecting the lift forces. In this manner, the lift
to drag ratio of the ball is adjusted upward.
As shown in FIG. 3, a preferred embodiment of the ball of the
subject invention includes a standard resilient body 20 as used in
prior art devices. However dimples 21 are concentrated in a band
extending about the sphere and centered about an imaginary plane
represented by the dotted line 22 passing through the geometric
center of the ball. The polar regions 24 and 25 are relatively
smooth surfaced in this embodiment. Of course the ball could also
be made with the surface depressions being more pronounced within
the band but of equal density as those outside the band.
The subject ball is teed in the position shown with the band
extending in a vertical plane in the direction of the intended
flight of the ball. Upon being hit, the ball spins about the spin
axis 26 extending through the midpoints of the polar regions 24 and
25. Lift of the ball is accomplished by the air film adjacent the
dimpled band. However, only a thin air film spins adjacent to the
regions 24 and 25 due to the smoother surface configuration. Thus
the lift exerted on the ball is substantially the same as for the
prior art ball since the areas of high lift are the same. However
the drag on the ball is decreased because less air film is carried
with the ball.
A further and more unexpected result occurs with the ball
heretofore described and shown in FIG. 3. If by chance the ball is
hit with a sidewise spin, which commonly causes a hooking or
slicing direction of travel, the resulting sidewise spin will
result in less curving of the flight path since less lift results
from the regions 24 and 25. Thus more control over the ball is
provided by the subject invention.
Tests have shown that if the ball is hit with a partial sidewise
spin, the subject ball will first start the curved flight commonly
called the hook or slice. The path of the ball will thereafter tend
to straighten out on a line close to the intended path and cease
following the curving, or arcuate, path originally caused by the
sidewise spin. One further factor tending to cause this unexpected
result may be the slightly greater weight at the polar regions of
the ball because of the lesser density of the dimples on the ball
surface. Thus, the ball exhibits what can best be described as a
"barbell effect"; that is, the ball always attempts to spin about a
longitudinal axis extending through both polar regions. As a
result, the sidewise spin ceases as the ball corrects itself in
flight, thereby doing away with the sidewise spin which otherwise
would cause further curving of the flight path.
Upon landing, the ball will assume any of a number of positions
relative to the green where it is ultimately desired to be
positioned. However the shots following the tee shot usually have
distance as a secondary requirement and if the ball is not aligned
to provide maximum lift, little effect results. The ball will
always have an equal amount of dimples and less dimpled surface
area to each side of a plane passing through the geometric center
and perpendicular to the spin axis such that little or no curving
of the flight path results from an unaligned lie. Further, if the
barbell effect does in fact correct the sidewise spin, the ball
will soon assume a spin about an axis perpendicular to the axis of
the dimpled band. The player need only allow for less lift if the
band initially does not align with the flight path. For putting,
the undimpled areas between dimples form an even spherical surface
for control of the ball.
In FIG. 4 is shown another embodiment of the ball wherein the
invention is incorporated in a ball 27 having central band 28 of
depressions. The depressions are formed by a series of grooves 29
extending from one smooth region 30 to the other smooth region 31.
The ridges 32 combine with the grooves to create turbulence thereby
to increase the film of air spinning with the ball as did the
depressions in the previous embodiment.
FIG. 5 illustrates still another embodiment of the invention
wherein the ball 34 has dimples 35 distributed over the total
surface area. However in this instance the dimples are within a
center band indicated by lines 36 and 37. Thus the turbulence
within this band is greatest thereby increasing the thickness of
the film adjacent thereto, while that adjacent to the cap regions
38 and 39 is less thick. Thus, control of the ball is increased in
the same manner as in previous embodiments with similar beneficial
results.
* * * * *